Systems and methods described herein generally relate to the field of medical ultrasound imaging. More specifically, embodiments described below relate to methods and systems which may be employed to generate images of interventional devices such as biopsy needles.
Conventional ultrasound imaging may be used to produce images of internal biological tissue structures. These images may be used to detect and diagnose internal abnormalities, to assist in medical interventions (e.g., real-time viewing of a needle during a biopsy procedure), or for any other purpose. Under many conditions, conventional ultrasound imaging produces images which are suitable for their intended purpose. However, under certain conditions and/or for certain purposes, images produced by conventional ultrasound imaging are not satisfactory.
FIG. 1 illustrates ultrasound imaging of a medical intervention. The area 150 includes internal tissue and a target lesion 140. During a biopsy, the biopsy needle 120 is inserted into the tissue from the skin surface to the target lesion 140 and under the ultrasound transducer 110. The needle 120 is therefore tilted with respect to the skin surface and the transducer 110.
To acquire a B-mode image, ultrasound beams are transmitted directly downward from the transducer 110 with no beam steering (0 degrees) and resulting ultrasound beams are then received by the transducer 110. Although only one ultrasound beam 170 is shown in FIG. 1, multiple ultrasound beams (e.g., a few hundred) may be transmitted. A B-mode image of the area 150 may then be created based on the received beams using known techniques.
The reflectivity of the needle at the illustrated entry angle is lower than the reflectivity of the needle if entering parallel to the transducer 110. Therefore, as shown in FIG. 1, an ultrasound image of the needle 130 will appear faint in the resulting B-mode image 150. As a result, it is difficult to guide the biopsy based on the B-mode image 150.